This invention relates to methods and apparatus for the application of biologicals onto field crops. More particularly, this invention relates to methods and apparatus for the application of predaceous or parasitic arthropods and/or living organisms onto field crops.
Chemical insecticides are commonly used to control insect pests that damage agricultural commodities. However, the use of chemical insecticides has several drawbacks including insecticide residue on commodities, resistance of insects, hazardous exposure to insecticides during application, environmental contamination, and destruction of natural biocontrol agents. Specific examples of the adverse effects of intensive chemical insecticide use are as follows:
(1) high level of tolerance to toxic compounds some insects have developed in recent years, leading to more frequent and heavier application of the toxic compounds to eliminate the pests; PA0 (2) an accumulation in the soil of non-biodegradable elements harmful to man; PA0 (3) absorption of toxic elements by the plant both through the root system and its foliage; PA0 (4) medical research linking the consumption of these toxic substances through food to certain diseases.
An alternative to chemical insecticides is the use of biological control agents. Biological control of insect pests involves the manipulation of certain beneficial organisms to reduce a population of pest organisms. The importance of biological control of insect pests in field crops has been recognized, and its use is rising. The use of biological control is especially desirable for high value fruit and vegetable crops grown for the fresh produce market, where the use of chemical insecticides is of concern to the consumer.
One technique for biological control is the augmentation of predaceous or parasitic arthropods which prey on selected pests. Recent advances in mass rearing beneficial arthropods, however, does not always result in successful biological control. For augmentation of beneficial arthropods to be successful in a field situation, mass releases of the beneficial arthropods must be achieved. For mass release of the beneficial arthropods to be effective, the arthropods must survive the distribution procedure and live long enough to find the pest insects. Problems with practical and reliable methods of distribution of the beneficial arthropods have prevented the wide-spread use of these alternatives to chemical insecticides. Another important consideration is cost of equipment and labor required for delivery of the beneficial arthropods.
In the past, parasite or predator insect eggs have been manually placed on plants, or attached to string which is then manually placed on individual plants (Tedders, Jr. et al. U.S. Pat. No. 5,484,504). The major disadvantage of this type of application is the time and labor involved in entering the field to manually place the eggs or egg-coated strings on plants. In an effort to provide more wide-spread application, Maedgen, Jr. (U.S. Pat. No. 4,260,108) teaches a method and apparatus for airborne release of insect eggs. This method has the disadvantage of requiring an airplane or other aerial application means and is restrictive to certain insects and developmental stages.
Predatory mites are another type of biological control agent, with its own distribution problems. Show (U.S. Pat. No. 4,966,329) teaches a field applicator for distributing predatory mites in a carrier material. The device consists of a container with interior baffles for mixing the mites and carrier material for even distribution. Show teaches variations of the device for manual application and an automated applicator attached to a vehicle. The automated version involves a plurality of applicators for simultaneously dispensing the mite and carrier mixture among a plurality of adjacent plant beds. Disadvantages of this type of automated device are that it must be taken into the field, it requires a carrier, and it requires mixing which is damaging to certain biological control agents.
Many methods of distributing biological control agents require workers alone or using machinery to repeatedly enter the field. This activity has the disadvantages of high labor costs and increased time required, which may prevent the consideration of biological control over chemical insecticides. Repeated passages through the field may also damage delicate crops, compact the soil after rain or irrigation, and may increase the distribution of weed seeds and pest insects throughout the field.
It has been discovered that many types of biological control agents can be delivered into a field by the use of an aerodynamic transport body (ATB). The aerodynamic transport body is a biodegradable delivery device which is projected into an agricultural field. Biological control agents are placed inside the delivery device. Upon landing in the field, the biological control agents exit the delivery device through an opening.